BIOL 251- MODULE 2: CONNECTIVE TISSUES

types of connective tissues

connective tissue proper: loose and dense

fluid tissue: blood and lymph

supportive tissue: cartilage and bone

types of connective tissue proper loose

areolar

adipose

reticular

areolar (CTPL)

the most common type of connective tissue proper

constitutes the tissue under the epithelium (lamina propria)

cells involved:

fibroblasts

macrophages, mast cells

adipocytes

fibers involved:

collagen

elastic

reticular

ground substance:

Gel-like ground substance high in hyaluronic acid, making it a highly hydrated thin, gel-like or viscous substance

functions: packing material (wraps and cushions), allows independent movement, has defense against pathogens

location: deep to the dermis of the body, between muscles and around joints

adipose (CTPL)

fatty tissue

cells involved:

adipocytes

fibers involved:

collagen and reticular

ground substance:

gel like

minimized due to how tightly compact cells are (high in number as well)

functions: energy reserves, insulating, padding (around eyes and kidneys), cushioning

location: deep to skin almost everywhere in body (prominent around buttocks and breasts)

Reticular (CTPL)

cells involved:

fibroblasts

reticular cells

Immune cells (macrophages, mast cells)

adipocytes

fibers involved:

predominately reticular

ground substance:

high hydrated and gel-like (thin or viscous) because it is high in hyaluronic acid (due to fibroblasts)

functions: providing a framework to resist distortion

location: soft organs like:

kidneys

spleen

liver

lymph nodes

bone marrow

types of connective tissue proper dense

regular, irregular, elastic

regular (CTPD)

has parallel collagen fibers that provide firm attachment and reduce friction between muscles and stabilizes bones in place

cells involved:

fibroblasts

immune cells

fibers involved:

collagen

ground substance:

gel-like but minimized due to sheer number of fibers

functions: withstand great tensile stress in ONE direction

location: tendons (muscle to bone), ligaments (bone to bone), and aponeuroses (connecting a large flat muscle to another muscle)

irregular (CTPD)

has no particular pattern of fibers

cells involved:

fibroblasts

immune cells

fibers:

collagen

ground substance:

gel-like but minimized due to sheer number of fibers

functions: withstanding great tensile stress in many directions

location:

covering visceral organs,

dermis,

peripheral nerves,

superficial layer of bones,

cartilage

elastic (CTPD)

cells involved: N/A

fibers involved:

elastic

ground substance: N/A

functions: recoiling after stretch

location: walls of blood vessels, erectile tissue of penis, bronchial tubes

fluid connective tissue types

blood and lymph

blood (FCT)

cells involved (formed elements):

erythrocytes (red blood cell)

leukocytes (white blood cell)

thrombocytes (platelets)

fibers: N/A

ground substance:

fluid plasma

function: supplying tissue with oxygen and removing CO2 (transportation of gases), carries nutrient, hormones and waste around the body

lymph (FCT)

created when fluid leaves the blood vessels and enters the lymphatic vessels

fluid is scanned for infection/toxins and then returned to the heart and CVS

this cyclic cycle allows body to maintain blood volume and remove toxins and waste

types of supporting connective tissue

cartilage and bone (osseous)

cartilage

avascular (antiangiogenesis)

has perichondrium surrounding it to separate from surrounding tissue

cells involved:

chondrocytes (contained within chambers known as lacunae which are suspended in matrix)

3 different types categorized by matrix

types of cartilage

hyaline, elastic, fibrocartilage

hyaline cartilage

most common type of cartilage

ground substance:

smooth, glassy, amorphous

semi solid

highly viscous

contains hyaluronic acid and chondroitin sulfate

fibers:

collagen and elastic

function: articular cartilage

protects, cushions and surround the ends of bones where they meet (reduced friction)

forms the embryonic skeleton

location: joints

elastic cartilage

ground substance: same as hyaline

fibers:

elastic

collagen

function: gives structure and flexibity

location: outer ear canal and epiglottis

fibrocartilage

ground substance: same as other 2

fibers: collagen

functions: resists compression and absorbs shock

location: between vertebrae and pubic bones

bone (osseous)

lacunae organize to surround blood vessels

canaliculi: passageways between lacunae in the bone matrix that allow cells to communicate

periosteum: layer that covers bone surface (tough fibrous outer layer and inner cellular layer) and anchors bones

cells: osteocytes, osteoclasts, osteoblasts (contained in lacunae)

fibers: collagen

ground substance:

calcium phosphate + bicarbonate (solid)

functions: resist shattering and compression, protects vital organs